There has been a running debate over the past 18 years as to whether psychoapthy is a “taxon”; “an entity, type, syndrome, disease, or more generally, a nonarbitrary class.” The concept goes back to Paul Meehl (1982; 1995) who laid out the importance of the concept for classifying psychopathology. Harris, Rice and Quinsey (1994) argued that psychopathy is a taxon, based on certain PCL-R Factor 2 items as well as childhood conduct disorder variables (which they incoporated in both the VRAG and SOARG, commonly used violence risk measures). The issue of categories vs. dimensions is a major issue in contemporary personality theory and assessment (should personality traits be considered discrete categories or as dimensional?), including current debates on revising the DSM 5, Axis 2 models of personality disorders. Generally, evidence of a psychopathy taxon has been weak in the literature (see Edens, et al, 2006). In their latest paper, Harris, Rice, et al., 2007, identify a “psychopathic sexuality taxon,” and conclude that coercive and precocious sexuality is a fundamental aspect of psychopathy. In response, Walters, G., and his colleagues (2011) published a strong response, based on taxometric research, that psychopathy is a dimensional construct. They argue against “reifying the existence of discrete psychopathological entities when the phenomenon in question in fact has dimensional underlying structure.”
The whole series of paper is a fascinating survey of competing models in psychopathology, personality assessment, and psychopathy with associated policy and public safety isses (see previous post on the Skeem et al (2010) psychopathy monograph).
Sources: Edens, J., Marcus, D. et al, (2006). Psychopathic, not psychopath: Taxometric evidence for the dimensional structure of psychopathy. Journal of Abnormal Psychology, 115, 1, 131-144.
Meehl, P. & Golden, (1982). Taxometric methods. In Butcher, J., et al. Handbook of research methods in clinical psychology.
Meehl, P. (1995). Bootstrap taxometrics. Solving the classification problem in psychopathology. American Psychologist, 50(4), 266-275.
Harris, Rice, & Quinsey (1994). Psychopathy as a taxon: Evidence that psychopaths are a discrete class. JCCP, 62,2, 387-397.
Harris, G., Hilton, et al ( 2007). Coercive and precocious sexuality as a fundamental aspect of psychopathy. Journal of Personality Disorders, 21, 1, 1-27.
Walters, G., et al . (2011). In search of the psychopathic sexuality taxon? Indicator size does matter. Behavioral Sciences and the Law, 29, 23-29.